Field of the Invention
The present invention relates to an electronic circuit for controlling a half H-bridge. A particularly advantageous, although in no way limiting, application of the present invention is in half H-bridge control circuits that are embedded in motor vehicles and that manage the supply of power to a load, such as an actuator.
Description of the Related Art
Various electronic circuits for controlling an H-bridge currently exist. Such a circuit is generally intended to manage the supply of power to a load, arranged in the center of said H-bridge, the latter being configured such that a given current flows from one terminal to another of said load in order to bias it. In the case of a motor vehicle, such circuits are embedded for the purpose of managing injectors or self-synchronous motors, for example.
The assembly formed of the control circuit and of the H-bridge traditionally has a symmetrical structure, including two identical parts arranged on either side of the terminals of said load. Therefore, the description of the features of one of two said parts, furthermore including a half of the H-bridge, termed half H-bridge, is sufficient for understanding the features of said assembly.
The half H-bridge conventionally comprises two transistors that are linked to a terminal of said load, managed by a control module and designed to switch between an off-state and an on-state.
Several types of electronic circuit for controlling a half H-bridge operating in accordance with the general principle described above, in particular those including two MOSFET (metal-oxide-semiconductor field-effect transistor) transistors of the same type, are known. They also generally include two separate control modules that independently couple the respective gates of said MOSFET transistors to a power supply line, or to an electrical ground, by means of a plurality of electronic components. These components accordingly necessitate, in addition to a non-negligible PCB (printed circuit board) area relative to the device in which they are embedded, a complex routing diagram with a view to ensuring compliance with electromagnetic compatibility standards.
Document JP H01 228319 proposes, to simplify the structure of an integrated power circuit for controlling an H-bridge on the one hand and to reduce the losses of said integrated power circuit on the other hand, inserting a parallel electronic circuit formed of resistors and of diodes. The resistors and the diodes are coupled to the gate of each of the P-channel MOSFET and N-channel MOSFET transistors of the parallel electronic circuit. Thus, when an input signal Vin changes to a high level, the P-channel MOSFET transistor is deactivated and the N-channel MOSFET transistor is activated, causing an N-channel MOSFET transistor of the power circuit to switch from an on-state to an off-state, and a P-channel MOSFET transistor to switch from an off-state to an on-state. The switching of the transistors of the power circuit causes an output signal of the power circuit to change to a high level. By virtue of the presence of the resistors and of the diodes, the transistors of the power circuit do not switch simultaneously.
Circuits including less elaborate electronics also exist, such as for example those including two MOSFET transistors of different respective types and that are coupled to a power supply by means of a single controller. Although such a configuration permits a saving in PCB area and a simplification of the routing diagram, said circuits are however not suitable, on the one hand, for completely preventing transconductance effects between MOSFET transistors or, on the other hand, for raising the load to high impedance in the event of a fault with the controller.